using System;
using System.Collections.Generic;
using System.Text;

namespace Buoi02
{
    abstract class CRectangular
    {

    }

    abstract class CRectangle2D : CRectangular
    {

    }

    class CFloat : CRectangle2D
    {

    }

    class FDouble : CRectangle2D
    {

    }

    class CRectangle : CRectangle2D
    {

    }
}
